1. Technical Field
The present invention relates to a light emitting diode type illuminating module having a capacity of from several watts to several tens of watts, and, more particularly, to a multipurpose light emitting diode type illuminating module which can greatly improve the heat radiation performance of an illuminating apparatus and can reduce the weight and size thereof because light emitting diodes (LEDs) generating a small amount of heat and having low power consumption as a light source are used.
2. Description of the Related Art
Generally, conventional security lights and street lights use a mercury or sodium lamp as their light source. Therefore, they are problematic in that energy consumption is high for lightness, and in that the lifecycle is short, so the light intensity rapidly decreases, thereby requiring periodic control.
Particularly, since the above-mentioned lights use mercury gas, there is a problem in that they cause environmental pollution when they are discarded.
Therefore, recently, illumination lamps, which use a light emitting diode (LED) having low power consumption and a long lifecycle as a light source, have been developed and appeared on the market.
In this case, the light emitting diode (LED), which is a semiconductor device having the advantages of rapid response speed, low power consumption and long lifecycle, produces minority carriers (electrons or holes) using a P-N junction, and emits light because of the recombination of the minority carriers. Therefore, the light emitting diode (LED) is advantageous in that it can greatly reduce the consumption of electric energy because its power consumption is about 1/10 that of a conventional incandescent bulb or halogen bulb.
Particularly, in the case of illuminating apparatuses requiring a large amount of electric power, such as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, etc., replacing the sodium or mercury lamps generally used in such an illumination device with light emitting diodes (LEDs) is very effective at reducing power consumption.
However, since conventional illuminating apparatuses using light emitting diodes (LEDs) are difficult to solve the problems of heat radiation, low-capacity light emitting diodes (LEDs) having a power consumption of 1 watt or less have generally been used. In other words, when high-capacity light emitting diodes (called power LEDs) having a power consumption of 1 watt or more, particularly, 2˜10 watts are used, a large amount of heat is generated. In this case, when the heat radiation performance thereof is low, peripheral devices are damaged by heat and the lifecycle thereof is rapidly shortened, so that these conventional illuminating devices cannot practically serve as illuminators.
Meanwhile, such illuminating apparatuses using light emitting diodes (LEDs), for example, security lights or street lights are advantageous compared to security lights or street light using fluorescence in that they have a simple lighting circuit, do not require an inverter circuit and an iron-core ballast, have low power consumption, a long lifecycle and low maintenance costs.
However, such illuminating devices as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, lights for sign boards, downlights, etc. are disadvantageous in that their properties are deteriorated by thermal stress and they easily break down.
That is, when the amount of electric current flowing to a plurality of light emitting diodes (LEDs) increases so that they can be operated, the amount of heat generated therefrom increases, thus causing the properties of the illuminating apparatuses to deteriorate and causing the illuminating apparatuses to break down.
For example, such illuminating apparatuses as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, lights for sign boards, downlights, room lights, etc., are provided with respective printed circuit boards (PCB) having a control circuit for switching LEDs on and off and a power circuit for externally supplying power to LEDs. The printed circuit board (PCB) malfunctions and breaks down by the thermal stress generated from the LEDs.
Therefore, in illuminating apparatuses such as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, lights for sign boards, downlights, etc., there have been many attempts to overcome the thermal stress generated from the LEDs by providing such a radiating plate as a heat sink or a slug made of a metal material having high thermal conductivity. However, in this case, there is a problem in that, due to the metal material constituting the radiating plate, the thickness and volume of the radiating plate increase in order to meet required heat radiating efficiency, which increases the size and weight of each of the illuminating apparatuses.
Moreover, in the case of conventional light emitting diode type illuminating modules or street lights, since it is possible to prevent the entry of moisture only when they are tightly closed, it is difficult to install a cooler for efficient heat radiation. Nevertheless, installing a cooler causes the problem of all kinds of foreign materials including water or moisture being introduced from the exterior into such illuminating apparatuses as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, etc.
Meanwhile, when a radiator used in a light emitting diode type illuminating module is formed by die-casting aluminum, there are problems in that the thickness and volume thereof are increased, so that the production cost thereof is increased and the weight thereof cannot be decreased, thus causing the production cost of a lamp stay or a lamp support heavier than a conventional discharge lamp to increase, and in that a previously-installed lamp stay or lamp support must be replaced by another.
Moreover, when a conventional discharge-type security light, floodlight or the like is replaced by a light emitting diode type security, floodlight or the like, the original light does not have a sufficient space in which to install a radiator required by the light emitting diode type security light, floodlight or the like, so that it cannot be directly used and is discarded, thereby causing the problem of a waste of resources.
Further, a conventional radiating structure formed by extruding or die-casting aluminum is somewhat excellent in thermal conductivity, but the heat radiation (thermal diffusion or discharge of heat to air) performance thereof is rapidly lowered in tightly enclosed locations.
For this reason, most radiating structures of LED illuminating apparatuses are formed by extruding or die-casting aluminum even though they have hardly been employed in notebooks or personal computers (PCs). However, they are problematic in that the volume and weight thereof are increased.
Further, conventional radiators using a principle of a heat spreader (called a self-powered heat pump) have lately been applied to high-price products such as notebooks and the like and LED illuminating apparatuses even though they have high performance but a short lifecycle, are expensive and have a large volume. However, they are problematic in that the prices of illuminating apparatuses become excessively expensive when they are used in the illuminating apparatuses.
Further, in conventional radiating structures formed by pressing, laminating and then bundling aluminum thin films, the thermal conductivity thereof is somewhat improved, and the thermal diffusivity thereof is greatly improved. However, they are problematic in that thermal diffusion is restricted in tightly-enclosed spaces, and in that the air layer located at the narrow space between the thin films has a thermal insulating effect. Therefore, it is not preferred that these conventional radiating structures be used in places where a large amount of dust exists.
Meanwhile, when such illuminating apparatuses as traffic lights, security lights, street lights, floodlights, lights for houses or cattle pens, lights for sign boards, downlights, etc. are fabricated using a light emitting diode type illuminating module, there are cases where it is required that the LED-type illuminating module be directly provided with a power supply converter, and, if necessary, there are cases where it is also required that a current controller, a color controller and a power supply converter are individually fabricated, and power sources and signal lines are respectively connected to the LED-type illuminating module.
However, among the above two cases, in the case where a power supply converter is independently and directly provided in the LED-type illuminating module, there is a problem in that the heat generated from the power supply converter provided in the LED-type illuminating module cannot be easily radiated because the power supply converter is installed in a housing formed of general synthetic resin having very low thermal diffusivity and thermal conductivity, and the heat generated from light emitting diodes (LEDs) can also be radiated only by a radiator, thus shortening the lifecycle of the LED-type illuminating module including the power supply converter and the light emitting diodes (LEDs).
Particularly, for example, when the LED-type illuminating module is a high-power illuminating module having a power of 10˜20 W, high heat radiation efficiency is required because each of the LEDs generates a very large amount of heat. However, conventionally, similarly to a low-power illuminating module having a power of 8 W or less, heat radiation is carried out only by one radiator integrated with several radiating fins, so that the size of the radiator becomes large or the heat radiation efficiency thereof becomes low at the same size, thereby shortening the lifecycle of the illuminating module itself including light emitting diodes (LEDs).